The increasing numbers of transportation facilities today and their higher load-carrying capacity necessitate a higher strength and reliability of springs and a lower metal consumption. The widely used prior art multi-leaf springs are made in the form of a stack of leaves having different lengths and a constant section throughout the length of each leaf. Such springs feature a high metal consumption, and are not sufficiently reliable due to interleaf friction in operation.
Known in the art is a spring leaf (cf. USSR Inventor's Certificate No. 647,048, cl. B 21 H 8/00 1/20, published in 1979) with constant-width main and additional bases, of which the additional base includes a middle part with a constant leaf thickness and two adjacent terminal parts with the leaf thickness diminishing from their junction with the middle part towards the leaf end faces. The leaf end faces in the given case have a greater thickness due to the fact that the requisite strength of the leaf is attained by increasing the thickness of its terminal parts located near the end faces thereof, which results in a higher consumption of metal required for the spring leaves and the spring as a whole.
Moreover, when stacking such leaves together they must be fixed relative to each other, which calls for special fasteners, specifically, leaf retainers, thereby resulting in fretting and breakage of leaves primarily at their junctions with the leaf retainers and in higher consumption of metal in the spring due to the necessity of using the retainers.